Refugia in glacial ages led to the current discontinuous distribution patterns of the dark red-backed vole Myodes rex on Hokkaido, Japan.

The terrestrial mammalian fauna of the North Japanese island, Hokkaido, is more similar to that of Southern Siberia than to the main island of Japan, Honshu. Three species of the genus Myodes (Muridae, Rodentia) are found on Hokkaido, but not on Honshu. While Myodes rufocanus and M.